Role of Collagen Derivatives in Osteoarthritis and Cartilage Repair: A Systematic Scoping Review With Evidence Mapping

Introduction: There is currently no diseasemodifying drug for osteoarthritis (OA), andsome safety concerns have been identified about the leading traditional drugs. Therefore,research efforts have focused on alternatives such as supplementation with collagen derivatives. The objective of this scoping review is to examine the extent, range, and nature of research, and to summarize and disseminate research findings on the effects of collagen derivatives in OA and cartilage repair. The purpose is to identify gaps in the current body ofevidence in order to further help progress research in this setting.Methods: The databases Medline, Scopus, CENTRAL, TOXLINE, and CDSR were comprehensively searched from inception to search date. After studies selection against eligibility criteria, following recommended methods, data were charted from the retrieved articles and these were subsequently synthesized. Numerical and graphical descriptive statistical methods were used to show trends in publications and geographical distribution of studies.Results: The systematic literature search identified a total of 10,834 records. Forty-one published studies were ultimately included in the review, 16 of which were preclinical studies and 25 were clinical studies (including four systematic reviews/meta-analyses). Collagen hydrolysate (CH) and undenatured collagen (UC) were the two types of collagen derivativesstudied, with a total of 28 individual studies on CH and nine on UC. More than a third ofstudies originated from Asia, and most of them have been published after 2008. Oral forms ofcollagen derivatives were mainly studied; three in vivo preclinical studies and three clinicaltrials investigated intra-articularly injected CH. In most of the clinical trials, treatment durationsvaried between 3 and 6 months, with the shortest being 1.4 months and the longest 11 months. All in vivo preclinical studies and clinical trials, regardless of their quality, concluded on beneficial effects of collagen derivatives in OA and cartilage repair, whether used asnutritional supplement or delivered intra-articularly, and whatever the manufacturers of theproducts, the doses and the outcomes considered in each study.Conclusions: Although current evidence shows some potential for the use of CH and UC as anoption for management of patients with OA, there is still room for progress in terms of laboratory and clinical research before any definitive conclusion can be made. Harmonization ofoutcomes in preclinical studies and longer randomized placebo-controlled trials in largerpopulations with the use of recommended and validated endpoints are warranted before collagen derivatives can be recommended by large scientific societies.